package com.ztcoding.shiSuDi.filter;

import com.alibaba.fastjson.JSON;
import com.ztcoding.shiSuDi.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 */
@Slf4j
@WebFilter(filterName = "LoginCheckFilter", urlPatterns = "/*")
public class LoginCheckFilter implements Filter {
    public static final AntPathMatcher PATH_MATCHER= new AntPathMatcher();
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1.获取本次请求的URI
        String requestURI = request.getRequestURI();
        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**"
        };

        //2.判断本次请求是否需要处理
        boolean check = check(urls, requestURI);

        //3.如果不需要处理，则直接放行
        if (!check) {
            log.info("本次请求不需要处理，直接放行");
            filterChain.doFilter(request, response);
            return;
        }

        //4.判断登录状态，如果已经登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("本次请求已经登录，直接放行");
            filterChain.doFilter(request, response);
            return;
        }

        //5.如果未登录则返回未登录状态，通过输出流方式向客户端响应数据
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
    }

    /**
     * 路径匹配 ，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls, String requestURI) {
        for (String url: urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                return true;
            }
        }
        return false;
    }
}
